Grinding machine-wheel wear compensating mechanism



July 14, 1959 c. c. ALVORD 2,894,360

' GRINDING MACHINE-WHEEL WEAR COMPENSATING MECHANISM Filed Dec. 20, 1956 5 Sheets-Sheet 1 INVENTOR CHAELEs C A1. voep Mum 'A TTOENE'Y July 14, 1959 I c. c. ALVORD 2,894,360

GRINDING MACHINE-WHEEL WEAR COMPENSATING MECHANISM! Filed Dec. 20, 1956 3 Sheets-Sheet 2 INVENTOR CHA ELES C. AL voep BY Mu-W A T'TOENEY 'July 14, 1959 c. c. ALVORD 2,894,360

GRINDING MACHINE-WHEEL WEAR COMPENSATING MECHANISM Filed Dec. 20, 1956 3'- Sheets-Sheet 3 L STOP INVENTOR CHARLES 6 A1. VOI

NZAALILW ATTOENEY United States Patent GRINDING MACHINE-WHEEL WEAR COMPEN- SATING MECHANISM Application December 20, 1956, Serial No. 629,532

7 Claims. (Cl. 51-165) The invention relates to grinding machines and more particularly to a grinding -wheel feed compensating mechanism.

One object of the invention is to provide a simple and thoroughly practical grinding wheel feed compensating mechanismautomatically to compensate for reduction in diameter of a grinding wheel caused by grinding wheel wear and truing. Another object of the invention is to provide a compensating mechanism which is built into the wheel feed apron. Another object of the invention isto provide a compensating mechanism which is interposed between the manually operable and the hydraulically'operated feeding mechanisms and the feed screw. Another, object is toprovide a feed compensating mechanism which is actuated in time relation with the grinding wheel 'truin'g apparatus.

j Another object is to provide a wheel feed compensating mechanism which is actuated automatically at the start of'each'r'ecip'rocation of the 'truing tool. Another object is to provide a readily accessible adjusting mechanism whereby the extent of compensation may, be regulated. Other objects will be in part obvious or in part pointed out hereinafter. l ,lnfthe accompanying drawings in which is. shown one of "various possible, embodiments of the mechanical featufrle's, ofjthis invention:

1 Fig. 1 is a fragmentary cross sectional view, through a cyli "cal grinding machine wheel feeding mechanism; .F is,v a fragmentary front elevation, on an enlarged seal 'of the wheel feed apron having par-ts broken away and'shown in section;

,Fig 3 is a fragmentary vertical sectional view, taken approximately on the line 3-3 of Fig. 2;

j Fig.4 is a fragmentary vertical sectional view, taken ximately on the'line 4--4.of Fig. 3;

p 5. is a fragmentary vertical sectional View, on an enlar ed; scale, taken approximately on either of the lines 5-5 of Fig. 4;, and

Fig ;"6. is a combined electric and hydraulic diagram of the actuating mechanisms and thecontrols therefor.

A grinding machine has been illustrated in the drawings comprising a base '10 which supports alongitudinally movable, work table 11 on a fiat way 12 and a V-way 1 3 io rmedfon'the upper surface of the base 10. The work table :11 may be traversed longitudinally either by a manually operable traversemechanism (not shown), or by a llydraulically operated mechanism includinga cylinder 14. This mechanism together with the wheel feeding mechanism to be hereinafter described are substantialfly identical with that shown in the prior US. Patent No. 2,572,529 to H. A. Silven, dated October '23, 1951., to which reference maybe had for details of disclosure not contained herein.

The base also supports a transversely movable wheel slide '20 which is arranged to slide transversely on a V-way 21 and a hat way (not shown) on the base :10. The wheel slide 20 supports a rotatable wheel spindle 22. in

2,894,360 Patented July 14, 1959 journalled bearings (not shown). A grinding wheel 23 is mounted on one end of the wheel spindle 22.

A Wheel feeding mechanism is provided comprising a rotatable feed screw 24, the right hand end of which is slidably keyed within a rotatable sleeve 25. The sleeve 25 is journalled in anti-friction bearings 26. The left hand end of the feed screw 24 is journalled in anti-friction bearings 27 carried by a slidably mounted sleeve 28 which is slidably mounted within a cylindrical aperture 29 formed in the base 10. The wheel slide 20 is provided with a depending feed nut 30 which meshes or engages the feed screw 24.

A hydraulically operated mechanism is provided for imparting an axial feeding movement to the feed screw 24 and a transverse feeding movement to the wheel slide 20. This mechanism comprises a cylinder 35 which is arranged in axial alignment with the feed screw 24. The cylinder 35 contains a slidably mounted piston 36 which is connected to the left hand end of a piston rod 37. The right hand end of the piston rod 37 is operatively connected to the slidably mounted sleeve 28 so that when the piston 37 is moved within the cylinder 35, a corre sponding movement will be imparted to the feed screw 24 and the wheel slide 20. This mechanism just described is utilized to provide a rapid approaching movement of the grinding wheel to rapidly position the wheel into operative relationship with the work piece to be ground. A control valve 38 is provided for controlling the admission to and exhaust of fluid from the cylinder 35. The control valve 38 is a conventional type piston valve similar to that shown in the above mentioned US. patent. The valve comprises a valve stem 39. A compression spring 40 serves normally to hold the valve stem 39 in a left hand end position. A solenoid 41 is provided which when energized serves to shift the valve stem 39 into a right hand end position. For details of disclosure not contained herein to which reference might be had to the above mentioned prior patent.

A manually operable feeding mechanism is provided comprising a manually operable feed wheel 45 which is rotatably supported on a shaft 46. The feed wheel 45 is provided with an adjustable stop abutment 45a and also with the usual micrometer adjusting mechanism 47 which is provided with a pinion 48 meshing with a gear 49 to facilitate adjusting the stop abutment relative to the feed wheel. A well known pivotally mounted stop pawl 4511., such as disclosed in the previously mentioned US. patent, is provided to be engaged by the abutment 45a to stop the counterclockwise rotation of the feed wheel 45 so as to terminate the infeeding movement of the grinding wheel 23. A gear 50 is fixedly mounted to rotate with the gear 4? and meshes with a gear 51 which is connected in a manner to be hereinafter described to rotate a shaft 52. The right hand end of the shaft 52 is journalled in spaced anti-friction bearings 53 and 54. The left hand end of the shaft 52 is slidably keyed within the sleeve 25.

A fluid pressure operated mechanism is provided to impart a rotary feeding movement to the feed screw 24 comprising a cylinder 60 which contains a slidably mounted piston 61. This fluid operated feeding mechanism is substantially identical with that shown in the above mentioned prior US. patent to which reference may be had for details of disclosure not contained herein.

A grinding wheel truing apparatus is provided for truing the operative face of the grinding wheel 23. The grinding wheel 23 is preferably partially surrounded by a wheel guard 65 (Fig. 6) which supports a truing apparatus 66. The truing apparatus is provided with a,

longitudinally traversable movable slide 67 which .is .ar-;

ranged to slide longitudinally on anti-friction slideways.

, 68. The slide 67 serves as a support for a vertically arranged sleeve 69 which is supported by anti-friction slideways 70. The sleeve 69 serves as a support for a truing tool spindle 71 which supports a truing tool 72 at its lower end. The upper end of the spindle 71 is provided with a feed screw 73 which meshes with or engages a rotatable feed nut 74. A feeding mechanism is provided for imparting a transverse feeding movement to the carrier sleeve and the truing tool 72. This mechanism may be identical with that shown in the prior US. Patent No. 2,647,504 to O. E. Hill, dated August 4, 1953, to which reference may be had for details of disclosure not contained herein. By this feeding mechanism, the truing tool may be fed downwardly automatically at each end of its longitudinal traversing stroke. A manually operable feed wheel 76 is provided by means of which the truing tool may be manually fed or adjusted as desired.

As illustrated in Fig. 6 the carrier sleeve 69 is provided with a follower 77 which rides upon the operative surface of a forming bar 78. As illustrated in Fig. 6 the forming bar 78 is provided with a plane operative surface so that a truing cylindrical surface will be trued upon the periphery of the grinding wheel 23 when the slide 67 is traversed longitudinally. If desired, the forming bar '78 may be provided with a shaped surface for generating a predetermined shape on the peripheral face of the grinding wheel.

A hydraulically operated mechanism is provided for traversing the slide 67 comprising a cylinder 80 which contains a slidable piston 81. The piston 81 is connected to the right hand end of a piston rod 82. The left hand end of the piston rod 82 is fixedly connected to the slide 67. When fluid under pressure is passed through a pipe 83, through a ball check valve 84 and a throttle valve 85, through a pipe 86 into the cylinder chamber 87, the piston 81 together with the slide 67 and the truing tool 72 will be traversed toward the right (Fig. 6). During this movement fluid within a cylinder chamber 88 exhausts through a pipe 89, through a throttle valve 90, through a pipe 91. A ball check valve 92 is provided so that when fluid under pressure is passed through the pipe 91, it may pass through both the ball check valve 92 and the throttle valve 90 into the cylinder chamber 88 to cause the piston 81 to move toward the left at a rate controlled by the throttle valve 85.

A fluid pressure system is provided for supplying fl ud under pressure to the operating mechanisms comprising a motor driven fluid pump 95 which may be started and stopped by actuation of a manually operable switch SW3. The pump 95 draws fluid through a pipe 96 from a reservoir 97 and passes fluid under pressure through a pipe 98 to a control valve 99. A relief valve 100 is connected in the pipe line 98 to facilitate by-passing excess fluid under pressure from the pipe 98 through a pipe 101 into the reservoir 97 to maintain a substantially uniform operating pressure within the fluid system.

The control valve 99 is a piston type valve comprising a slidable valve member 102 having a plurality of spaced valve pistons formed integrally therewith to form spaced valve chambers 103, 104, and 105. The valve member 102 is provided with a central passage 106 which interconnects the valve chamber 103 with the valve chamber 105. A compression spring 107 serves normally to hold the valve member 102 in a left hand end position. A solenoid S1 is provided which when energized serves to shift the valve member 102 into a right hand end position thereby reversing the flow of fluid under pressure between the control valve 99 and the cylinder 80.

In the position of the valve 99 (Fig. 6) fluid under pressure entering the valve chamber 104 passes through the pipe 91, through both the ball check valve 92 and the throttle valve 90, through the pipe 89 into the cylinder chamber 88 to move the piston 81 toward the left into the position illustrated in Fig. 6.

' When the solenoid S1 is energized to shift the valve A member 102 into a right hand end position fluid entering the valve chamber 104 passes through the pipe 83, through the ball check valve 84 and the throttle valve 85, through the pipe 86 into the cylinder chamber 87 to move the piston 81 toward the right at a rate controlled by the throttle valve 90.

The truing apparatus is arranged so that a manually controlled intermittent truing operation may be obtained in which case the diamond or truing tool 72 is passed across the operative face of the grinding wheel 23 through one complete reciprocation, that is, toward the right and then toward the left. At each end of the stroke of the truing tool a predetermined down feed is obtained in a manner similar to that disclosed in the above mentioned US. Patent No. 2,647,504. If desired, a continuous truing cycle may be obtained in which the truing tool is reciprocated continuously across the operative face of the grinding wheel 23.

When it is desired to true the grinding wheel, a manually operable start switch SW1 is momentarily closed to energize relay switch CR1 which closes a pair of contacts 110 and 111. The closing of contacts 110 sets up a holding circuit through the normally closed limit switch LS1. The closing of contacts 111 serves to energize the solenoid S1 to shift the valve member 102 toward the right thereby passing fluid under pressure into the cylinder chamber 87 to traverse the piston 81, the slide 67 and the truing tool 72 toward the right to true the operative face of grinding wheel 23. When the truing tool slide 67 approaches the right hand end of its stroke, it opens the normally closed limit switch LS1 thereby breaking the holding circuit to deenergize the relay switch CR1 thereby deenergizing the solenoid S1 so that the released compression of the spring 107 shifts the valve member 102 into a left hand end position. In this position of the control valve 99, fluid under pressure is passed into the cylinder chamber 88 to traverse the piston 81, the slide 67 and the truing tool 72 toward the left to again true the operative face of the grinding wheel 23. When the truing tool slide 67 reaches the left hand end of its traverse, it stops in a position ready for the next truing cycle. For each actuation of the start switch SW1, the slide 67 will make one complete reciprocation and then stop. If it is desired to stop the truing cycle at any time during its truing operation, a stop switch SW2 may be actuated to open the circuit so as to break the holding circuit thereby deenergizing the relay switch CR1 so that the slide 67 will return immediately to its left hand end position.

If a continuous truing cycle is desired, a manually operable switch 112 is closed. The closing of the switch 112 serves to energize the relay switch CR1 and the slide 67 traverses toward the right and reverses in a manner the same as previously described. As soon as the slide 67 starts moving toward the right, the normally open limit switch LS2 opens. When relay switch CR1 is energized by closing of the switch 112, a holding circuit is set-up through the limit switch LS1 so as to maintain the relay switch CR1 energized after the limit switch LS2 opens so as to facilitate a traversing movement of the slide 67 toward the right. As the slide 67 approaches the right hand end of its stroke the normally closed limit switch LS1 is opened to break the holding circuit thereby deenergizing the relay swicth CR1 and deenergizing the solenoid S1. The slide 67 then traverses toward the left. As the slide 67 approaches the left hand end of its stroke, it closes the normally open limit switch LS2 which serves to again energize the relay switch CR1 thereby starting a traverse movement of the slide 67 toward the right. This continuous reciprocation of the slide 67 continues as long as the switch 112. remains closed. When it is desired to stop a continuous truing cycle, the switch 112 is open thereby rendering the limit switch LS2 inoperative so that the slide 67 will stop after.

each reciprocation thereof.

In order to obtain the principal object of this invention a simplified wheel feed compensating mechanism is provided automatically to impart a rotary motion to the feed screw 24 thereby adjusting the wheel slide 20 and the grinding wheel 23 by an amount equal to the wheel wear and reduction in diameter of the wheel caused by the truing operation. As illustrated in the drawings a wheel feed compensating mechanism 115 is mounted on the gear 51. This compensating mechanism serves to operatively connect the gear 51 with the shaft 52 which is connected to rotate the feed screw 24. A worm gear 116 (Fig. 3) is provided with an integral hub 117 which is keyed to the shaft 52. The outer peripheral surface of the hub 117 serves rotatably to support the gear 51. The worm gear 116 meshes with a worm 119 fixedly mounted on a rotatable shaft 119a (Fig. 4) which is rotatably supported by a pair of spaced antifriction bearings 120 and 121 which are supported within a frame 122 which is fixedly mounted on the side face of the gear 51. A gear 123 is provided on the left hand end of the shaft supporting the worm 119. The gear 123 meshes with a gear 124 (Figs. 2 and 3) which is mounted on a rotatable shaft 125. A gear 124a on the shaft 125 meshes with a rack 126 formed on the periphery of a piston 127 (Fig. 3). The piston 127 is slidably mounted within the cylinder 128 which is formed within the right hand end of the shaft 52. When fluid under pressure is passed througha pipe or passage 129 into a cylinder chamber 130, the piston 127 is moved toward the right (Fig. 3) against the compression of a spring 131. A slidably mounted plunger 132 is slidably sup'ported within the piston 127 and is urged in a direction toward the right into engagement with the ju a op screw 133- When the piston 127 is moved toward the right (Fig. 3) to impart a compensating adjustment to the feed screw 24, this movement continues against the compression of the spring 131 until a stop surface 134 at the right hand end of the piston 127 engages a stop surface 135 on the plunger 132. It will be readily apparent from the foregoing disclosure that by manipulation of the stop screw 133, the extent of movement of the piston 127 may be varied as desired to obtain the desired compensating adjustment of the feed screw 24. A ball clutch 140 is provided between the shaft supporting the worm gear 119 and the gear 123. When the piston 127 moves toward the right a rotary motion is imparted through the rack 126, the gear 124a, the shaft 125, the gear 124, the gear 123, the ball clutch 140 to impart a rotary motion to the worm 119 and the shaft 119a in a clockwise direction (Fig. 3). Rotation of the worm 119 imparts a. rotary motion to the worm gear 116 which in turn imparts a rotary compensating adjustment to the feed screw 24 so as to compensate for the reduction in diameter of the grinding wheel caused by wheel wear and the truing operation. This compensation takes place when the solenoid S1 is energized and the valve member 102 is shifted into a right hand end position to pass fluid through the pipe 83 into the cylinder chamber 87 to start a traversing movement of the piston 81 together with the slide 67 and the truing tool 72 toward the left. At the same time fluid passing through the pipe 83 passes through the pipe or passage 129 into the cylinder chamber 130 to impart a compensating adjustment to the feed screw 24 at the start of each reciprocation of the truing tool 72.

When the truing tool slide 67 reaches the right hand end of its stroke, it opens the normally closed limit switch LS1 thereby breaking the holding circuit to deenergize the solenoid S1 so that the released compression of the spring 107 shifts the valve member 102 into the position illustrated in Fig. 6. In this position of the valve 99, the released compression of the spring 131 moves the piston 127 toward the left (Fig. 6) to exhaust fluid from the cylinder chamber 130, through the passage 129,

through the pipe 83 into the valve chamber 105, through the central passage 106 into the valve chamber 103 and exhausts through the pipe 101 into the reservoir 97. During this resetting movement of the compensating mechanism, the gear 123 rotates idly in a clockwise direction and due to the ball clutch 140 does not impart any rotary motion to the shaft 1 19a. During this resetting movement, a ball clutch 141 (Fig. 4) which is interposed between the shaft 119a and an end cap 142 which is fixedly mounted on the casing 122 serves to hold the shaft 119a against rotary motion in the reverse direction. The ball clutch 141 is identical with that shown in Fig. 5.

-When the truing apparatus is operated intermittently over the manual control of the switch SW1, the compensating mechanism above, described makes one compensation before the first pass of the truing tool 72 across the face of the grinding wheel 32. If the switch 112 is closed and a continuous truing cycle started, the compensating mechanism is actuated at the start of each reciprocation'of the truing tool 72, that is, each time the truing tool 72 starts its movement toward the right (Fig. 6).

The hydraulic connections between the control valve 99 and the cylinder 128 have been diagrammatically illustrated in Fig. 6. In actual construction, as shown in Fig. 3, fluid under pressure passing through the pipe 83 passes not only to the cylinder but also to an annular groove 143, through radially extending holes 144 through the passage 129 into the cylinder chamber 130.

The operation of this improved compensating mechanism will be readily apparent from. the foregoing disclosure. Assuming the mechanism to have been previously adjusted, that is, the stop screw 133' adjusted to facilitate a predetermined compensation, the switch SW3 is closed to start the fluid motor 95. When it is desired to true the grinding wheel by an intermittent cycle, the switch SW1 is manually closed to initiate a truing cycle, that is, one complete reciprocation of the truing tool 72 across the operative face of the grinding wheel 23. At the start of the truing cycle fluid under pressure is passed through the cylinder chamber to impart a compensating adjustment to the wheel feed mechanism previously described. If a continuous truing of the grinding wheel 23 is desired, the switch 112 is closed thereby energizing the relay switch CR1 to start a reciprocation of the truing tool 72. At this time the fluid under pressure is passed through the cylinder chamber 130 so as to actuate the feed compensator at the start of a reciprocation of the truing tool 23. With the switch 112 closed, the truing tool 72 is reciprocated continuously across the operative face of the grinding wheel 23 and at the start of each reciprocation thereof a compensating adjustment is imparted to the feed screw 24.

It will thus be seen that there has been provided by this invention a grinding wheel truing apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth as shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a grinding machine having a base, a transversely movable rotatable grinding wheel thereon, means including a nut and screw feeding mechanism operatively connected to feed said grinding wheel in either direction, feeding means to impart a rotary feeding movement to said feed screw so as to impart grinding feed to said wheel, and an independent feed compensating mechanism interposed between said feeding means and said feed screw to facilitate a predetermined incremental actuation of the feed screw so as to automatically compensate for wheel wear.

2. In a grinding machine having a base, a transversely movable rotatable grinding wheel thereon, means including a nut and screw feeding mechanism operatively connected to feed said wheel transversely in either direction, a rotatable gear to actuate said nut and screw mechanism to impart a grinding feed to said Wheel, means to impart a rotary motion to said gear, an independent feed compensating mechanism on said gear, and operative connections between said gear and the feed screw to facilitate automatically imparting a predetermined compensating adjustment to the feed screw to compensate for wheel wear.

3. In a grinding machine having a base, a transversely movable Wheel slide thereon, a rotatable grinding wheel on said slide, means including a rotatable feed screw and a nut to impart a transverse feeding movement to said slide, a rotatable gear, a manually operable feed wheel to impart a rotary motion to said gear to actuate said screw mechanism to impart a grinding feed to said wheel, a fluid motor to impart a rotary motion to said gear, an independent wheel feed compensator mounted on said gear, and operative connections between said compensator and said feed screw to connect the gear with the feed screw to facilitate automatically imparting a predetermined compensating adjustment for grinding wheel wear.

4. In a grinding machine, as claimed in claim 3 in combination with the parts and features therein specified of a longitudinally traversable truing tool for truing the operative face of the grinding wheel, means to traverse said truing tool in either direction, and means to actuate said compensator mechanism in timed relation with the start of the longitudinal traversing movement of the truing tool to impart a rotary motion to the feed screw relative to said gear so as to compensate for wheel Wear.

5. In a grinding machine, as claimed in claim 3, in combination with the parts and features therein specified of a longitudinally traversable truing tool for truing the operative face of the grinding wheel, means includ- 8 ing a fluid motor to traverse said truing tool in either direction, and means including a fluid motor actuated in timed relation with said first motor to actuate said compensating mechanism to impart a rotary motion to the said feed screw relative to said gear at the start of each truing cycle so as to compensate for wheel wear.

6. In a grinding machine as claimed in claim 3, in combination with the parts and features therein specified of means including a piston and cylinder to traverse said truing tool in either direction, means including a piston and cylinder to actuate said compensating mechanism, and a control valve operatively connected to control the admission to and exhaust of fluid from both of said cylinders, said second piston and cylinder being arranged to impart a compensating adjustment to said feed screw at the start of each truing cycle so as to compensate for wheel wear.

7. In a grinding machine, as claimed in claim 3, in combination with the parts and features therein specified of a shaft operatively connected to rotate said feed screw, a feed gear rotatably supported by said shaft, a rotatable feed wheel to rotate said gear, a cylinder within said shaft, a piston slidably supported by said cylinder, a feed compensating mechanism operatively connected between said gear and shaft, operative connections between said piston and said compensating mechanism to impart a rotary compensating adjustment to said feed screw, and means including an adjustable stop screw to limit the extent of movement of said piston to facilitate varying the amount of compensation.

References Cited in the file of this patent UNITED STATES PATENTS 762,838 Norton June 14, 1904 1,044,308 Wagner Nov. 12, 1912 1,584,339 Wernecke May 11, 1926 2,137,644 Cole Nov. 22, 1938 2,334,581 Pyne Nov. 16, 1943 2,572,529 Silven Oct. 23, 1951 

